Automatic slack adjuster



Oct. 27,1925 1,559,143

A C. O. ANDERSON AUTOMATIC SLACK ADJUSTER Filed Sept. 17, 1923 a! K 39 36 a9 5 32 33 Z7 20 23 1 j v a 3O 29 34- ave/M101 C. O. Auneasou.

Patented st. 27, 1925.

ED S T A '1 E S 1,559,143 PATENT cr tic-E.

cHAn EsoscnR ANDERSON, or OMAHA, NEBRASKA, AssIenoR #ro ANDERSON BRAKE A ER Q ANY, 0F M A BR SKA, A CQRIORATION OF-NEBRASKL AUTOMATIC sneer; An usTEB;

Application filed September 1 7, 1923. s er ial N 53 8 To all whom it may concern:

Be it, known that I, G-HAnLns Oscar:

Annnnson, a citizen of the ;United States,

residing atOmaha, in the county of-Douglas 6 and-State, of Nebraska, have invented o'er new and useful Improvements in Automatic-Slack Adjusters, of which the following isa specification.

,My invention relates to railway brake is apparatus, and particularly to automatically operated adjustingdeviccs for maintaining t Constant clearance between the wheels and brake-shoes when the brakes are in release position, wherebyv .to constantly compensate the wear of the brake-shoes, so that apply-' ing of the brakes is effected by uni-form travelof the brake-actuating means. jIt is the objectv of my invention to provide a simple and efficient brake-adjusting device 20 of this character, especially adaptable for use 'intcaseswhere there is abrake-beam and equalizer-beam consisting of'flat bars disposed adjacent 2'60 eachother in a common plane.

In the accompanying drawings 1 is a plan view of a truck-frame and brakeriggging having my automatic adjuster applied. thereto, 2 is a detail plan view of the adjuster, andFig. 3 is a side view of the same, a portionjbe'ing in longitudinal section.

in thetruck-frame representedin Fig. 1 the longitudinal side-members 10' have'the usual cross-bracingll and journal-boxes 12,

35 the axles Bandwheels 1 1 being represented indotted outline only, At each end of the,

frame are the transversely extending brakebeams of which the ends are adjacent to the wheels l landhave the usual brake-heads lGto whichare secured the renewable brakeshoes 17. supported by pivoted hangers 18 depending 4 from the hanger-rods 19 which extend'transr versely zbetweenthe side frame-members 10 above the Lbrake-beams. Each brake-beam is formed by a flat-bar disposedhorizontally edgewise, and the (equalizer-beams 20 are formed by similar bars-of less length, (11S- posed parallel with. the brake-beams and adjacent to theedgesthereo f opposite the wheels. The ends of theequa'liz'er-beams are connected with each other by longitudinal :rods 21, whereby any movement of one beam is ,communicated to the 3 other. N ar the en er 94 each equalizer-beam is The brake-beams are swingably secured a strut22 which extends outwardly, or longitudinally of, the truck away from the respective brake-beam. Upon said struts 22 fulcrumed the brake lev ers 23 which extend therefrom laterally, and t0 the longer arms ofthe brake-levers are connectedthc brake-rods '24:, by means of which the brakes are applied, In t'he usual construction of this type of brake-rigging, the short arm .of each brake-lever is. connected with the, respective brake bea nbya yoke or j-cle' vis 25 which straddlesthe equalizenbeam and is, connected'with the brake-beam near the center thereof, wear of the brake-shoes being compensated by means of turnbilfikles 26 Whichvary the effective length of the rods 21 connecting the ends of the equalizerbeams. In equipping the brake-rigging with my automatic adjuster, the latter replaces the clev'is connection between the brake-lever and brake-beam at one end of the truclgwhile at the other end the usual connection is left undisturbed, as shown at the left of Fig. 1.

The automatic adjusting device has a clevis consisting of a pair of symmetrical arms 27 which straddle the beams 15 and 20, and at their forward ends are connected with the short arm of the brake-lever 23 by means o-fthe pivot-bolt 28. Bearwardly of.

the, brake-beam the endportions of the clevis-arms 27 form the upper and lower.

halves of. a split cylindrical head 29, of, which the terminal portion is threadedv to. receive the collar 30 by which the two parts of the head are secured together. WVithin the head 29' is revo'lubly fitted the spool.- sh'aped bodyf311 of the adjusting-sleeve, which is threaded internally to receive the adjusting-screw 32. The latter extends for: wardlyfiomtlie sleeve between the clevisarms 27 and has a forked head 33 which straddles the bnakebeam and. to which it is pivotally connected by the bolt 3% Said bolt also extends through the longitudinal slots 35 in the clevis-arms, the bolt fitting slidably in said slots and constituting, a

de Li a ing he levis an adius i a screw inlongitudinal aline nent. At the end,

of the adjusting sleevebody 31 there isa tubular, extended portion 3619f which the screw, wlienebythe screw may freely enter .saidtubular portion. At the rear end of the boreis of, slightly greater diameter thanthe 37, to which a. wrench is applied when resetting the adjuster for the insertion of new brake-shoes. The clutch-sleeve 38 is dis posed about the extended portion 36 of the adjusting-sleeve, the latter having a conical clutch-surface 39 with which the conicallybored end-portion of the sleeve 38 is frictionally engaged. The rear end of the clutch-sleeve is engaged at diametrically opposite points by the ends of a shouldered cross-pin 40 which extends through a slot in the adj Listing-sleeve at the juncture of the portions 36 and 37. The intermediate portion of said cross-pin 40 passes through the head of a plunger 41, which has a stem extending through the end of the part 37. A coil spring 42 is disposed about the plungerstem between the head thereof and the end of the part 37. The pressure of said spring is communicated by the cross-pin to the end of the clutch-sleeve and tends to move said sleeve longitudinally of the part 36, to thereby hold the clutch-sleeve in yielding engagement with the conical clutch-surface 39 of the adjusting-sleeve. For convenience in assembling and disconnecting the parts, a portion of the plunger-stem which protrudes from the part 37 has a transverse slot 43 through which a wedge may be inserted to move the plunger reaiwvardly and disengage the cross-pin from the end of the clutchsleeve. 'lVhen the plunger has been moved 'back far enough to withdraw the shoulders of the cross-pin. from within the end of the clutch-sleeve, the cross-pin may be removed, after which the clutch-sleeve may be withdrawn off the end of the adjusting-sleeve. Normally, the spring pressure upon the plunger retains the cross-pin in the position at which its shoulders enter the end of the clutch-sleeve, and the pin is thereby prevented from accidental. dislodgment. A movable screw-plug 44 is provided at the upper side of the clutch-sleeve, for convenience in introducing a lubricant into the space between said sleeve and the adjustingsleeve. In the side of the inner sleeveportion 36 there is an oil-hole 45 through which the lubricant may enter and thus reach the threads of the adjusting-screw. At the upper side, near the front end of the clutchsleeve, there is a U-shaped vertically extending flange 46 adapted to receive the sphero segmental head at the end of one arm of the bell-crank 47, the latter being mounted pivotally upon a stud 48 secured to the upper side of the clevis-head 29. The other arm of the bell-crank extends laterally of the clevis, and to the end thereof is pivotally connected the rear head 49 of a rod 50 which extends forward parallel with the clevis-arms. At its front end the rod 50 is threaded and is screwed into a slotted head 51, a locknut 52 being provided on the rod adjoiningthehead. The end of the rod is extended into the rear portion of the slot in the head and forms an abutment or stop for limiting in one direction the relativemotion of the head and the pin 53 which extends through the slot. Said pin 53 is an upward extension of the fulcrum-pin which connects the brake-lever with the strut 22 of the equalizer-beam. A washer and cotter-pin at the upper end of the pin 53, as shown, serve to hold the head 51 in place thereon.

Any suitable release-springs may be pro vided in connection with the brake-beams for moving the brake-shoes out of contact with the wheels except when the beams are moved to braking position by tension upon one of the rods 24. The release-springs are not shown in the drawing, but it will be understood that any ordinary arrangement thereof may be employed. Applying of the brakes, or movement of the brake-beams to engage the brake-shoes with the wheels, is caused by movement of either brake-rod 24 while the other is held stationary. During the applying movement, the brake-beam and equalizer-beam at each end of the truck move apart, or relatively away from each other, their approximate relation at release and applied positions being indicated, respectively, by the full-line and dotted-line representationsof the beams in Fig. 2. In said figure is also shown in full and dotted lines, respectively, the release and applied positions of the brake-lever, corresponding with a normal brake-shoe clearance at release position. It will be seen that during the brake-applying and releasing movements the fulcrun'i-pin 53 will move longitudinally of the slot in the head 51 of the rod 50, since the fulcrum-pin moves with the equalizer-beam, while the rod 50 tends to move with the clevis and brake-beam. The length of the slot in the head 51, from the front end to the adjustable abutment formed by the end of the rod, is made such that during a normal travel of the parts the fulcrumpin will merely move from end to end of the slot, while a movement in excess of the established minimum or normal motion will cause the rod 50 to be moved longitudinally an amount corresponding to the excess travel of the fulcrun'i-pin. Thus, whenever there is an excessive travel of the parts .in applying and releasing the brakes, such excess movement will result in a longi tudinal reciprocation of the rod 50, its forward motion occurring at the end of the applying movement, and its rearward motion being at the end of the releasing movement. The longitudinal reciprocating motion of the'rod 50 causes an oscillation of the lever or bell-crank 47 about the stud 48, and the motion of the rear arm of the bell-crank causes a slight rotation of the clutch-sleeve about its axis in alternating directions, the sphere-segmental form of the head at the end of the bell-crank allowing the rocking motion of the sleeve, relative to the arm,-..to take place without causingbinding between said head and the U-fiange 46.- 13y; reason of the. frictional engagement of I the clutch-: sleeve with theclutch-surface 39- OfFthe: ad-' justing-sleeve, the latter tendsto move with the clutch-sleeve, .and such movement of the adjusting-sleeve willoccur if the friction at the clutch-surface is: greater than the re-- tar-ding-friction upon the adjusting-sleeve, said retarding-friction :being thesum of the friction between the sleeve andv screw' 32 and between the sleeve andthe clevis-head 29. If the i retarding friction is greater than the (hitch-friction, then the clutch will slip and no movement of the adjusting-sleeve will be caused. The parts are so proportioned that the last-named condition will prevail during the movement of the clutch-sleeve caused by applying the brakes, the retarding-friction being greater at this time because of the pressure of the clevis head against the adj tlStlllg-SlGGVG, and the pressure of the latter against the threads of the screw 32. At the end of the releasing movement, however, the retarding-friction is greatly reduced, and becomes less than the clutch-friction, so that the movement of the clutch-sleeve results in turning of the adjusting-sleeve. The direction of this movement is such that the screw 32 is moved rearwardly or into the sleeve, and the brake-beam is thereby moved closer to the rear end or head 29 of the clevis. The clearance between the brakeshoes and wheels is thus reduced, so that less movement of the brake-lever is required at the next application of the brakes. If, however, the brake-shoe clearance is still too great, so that excess movement of the parts is required to apply the brakes, the clutchsleeve will be again actuated, and a further adjustment automatically effected upon the releasing of the brakes; the adjusting action being continued at each application and. release of the brakes until the clearance is re duced to the desired normal. As hereinbefore mentioned, when the brake-shoes have been worn out and before new brake-shoes are inserted, the automatic adjusting mechanism is reset by applying a wrench to the hexagonal end 37 of the adjusting-sleeve, and said sleeve turned in the direction opposite to that in which it is moved by the clutch, until the clearance between the brake-heads and wheels is 'suflicient to' receive the new shoes,

New, having described my invention, what 1 claim and desire to secure by Letters Patent is:

1. In a railway brake mechanism, the comable from and toward each othe'rato apply and release the brakes, av brake-lever fulcrumed on the equalizer-beam,and an actuating member connected with the brakelever, of a clevis comprising a" head and spaced arms straddling the brake-beam and equalizer-beam and pivotallyvconnected iwith the-brake-lever, a rotatable. adj Listing-sleeve held infixed' longitudinal relati'on'to said clevis-head, an adjus'ting:screw having one end connected with the brake beam and a threaded portion engaging the adjustingsleeve, a-=clutch-sleeve mounted on swidad j ustingsleeve and held in frictional engagement therewith, andnneansactuated during excess; travel of-the' brake-lever for rotating said'clutch-sleeve in alternating directions at the ends of the brake-applying and brake-releasing movements.

2. Automatic slack-adjusting means for brake-mechanism having a brake-beam and equalizer-beam adjacent to and relatively movable from and toward each other to apply and release the brakes, comprising a brake-lever fulcrumed upon the equalizerbeam, a screw-threaded member connected with the brake-beam and extending therefrom at the side opposite the equalizer-beam, a threaded adjustingsleeve engaging said screw-threaded member, a clevis having a head in which said adjusting-sleeve is held revolubly, said clevis having arms straddling the brake-beam and equalizer-beam and pivotally connected with the brake-lever, a clutch-sleeve mounted coaxially with the adjusting-sleeve and frictionally engaged therewith, a lever fulcrumed on the clevishead and having an arm connected with the clutch-sleeve, and arod pivotally connected at one end with said lever and at the other end connected loosely with the brake-lever fulcrum-pin, whereby said rod and lever are actuated to rotate the clutchsleeve during the brake-applying and releasing movements when the relative motion of the brake-beam and equalizer-beam is greater than normal.

3. A structure as set forth in claim 1, in which the clevis-'head is divided in an axial plane, each portion of the head being integral with one of the arms, the adjustingsleeve having a spool-like portion of which the central part is embraced by the head and the end-flanges abut the ends of the head to prevent relative axial movement of the sleeve and head, and an integral annular collar surrounding the headvto hold its parts together.

4. A structure as set forth in claim 2, in which the loose connection between the rod and brake-lever fulcrum-pin comprises a head having a longitudinal slot through which the fulcrum-pin extends, the end of the rod being threaded and said head. screwed thereon, the end of the rod extending into a part of the slot in the head and forming an adjustable abutment for limiting movement of the fulcrum-pin in said slot.

5. A structure as set forth in claim 2, in which the frictional engagement between the clutch-sleeve and adjusting-sleeve is effected by means of a spring inelosed in a portion of the adj listing-sleeve which protrudes from the end of the clutch-sleeve, a plunger engaged by the spring and having a stem extending through the end of the adjustin -sleeve, and a cross-pin extending transversely through said plunger and through longitudinal slots in the adjustingsleeve, the ends of said pin being shouldered and engaging the end of the clutchsleeve.

6. A structure as set forth in claim 1, in Which the adjusting-screw has a forked head fitting about the brake-beam and be tween the clevis-arms, said arms being 1ongitudinally slotted and a bolt' extending through the brake-beam and forked head to pivotally connect the same, said bolt extending also through the slots of the elevisarms and fitting slidably therein as a guide for holding the clevis and adjusting-screw in longitudinal alinement. v

CHARLES O. ANDERSON. 

